Technical Description

Two vulnerabilities have been identified in Postfix, which could be exploited by malicious users to bypass security restrictions, gain knowledge of sensitive information, or potentially obtain elevated privileges.

The first issue is caused due to Postfix allowing the delivery of mails to root-owned symlinks in an insecure manner, which could allow a local attacker (with write permissions for the spool mail directory) to append a mail to an arbitrary file.

The second weakness is caused by an error in the delivery agent that does not properly verify the ownership of a mailbox before delivering mail, which could allow local attackers (with write permissions for the spool mail directory) to create a previously nonexistent mailbox before Postfix creates it, allowing them to read the mail of another user.

Affected Products

Postfix versions 2.x

Solution

Upgrade to Postfix 2.5 Patchlevel 4 :
http://www.postfix.org/download.html

References

http://www.vupen.com/english/advisories/2008/2385
http://marc.info/?l=postfix-announce&m=121871575128717&w=2
http://lists.opensuse.org/opensuse-security-announce/2008-08/msg00002.html

Credits

Vulnerabilities reported by Sebastian Krahmer (SuSE Security-Team).

ChangeLog

2008-08-15 : Initial release

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